The US size for ring 21 is 10-11. The ring size range in China is 4-26, in Europe it is 44-61, and in the US it is 5-12. Therefore, ring size 21 belongs to the Chinese ring size range, with a circumference of 63mm and a diameter of 19.2mm. According to the international ring size comparison table, ring size 21 is equivalent to US sizes 10-11.
What to pay attention to when measuring ring size
1. It is recommended to choose a thin rope or paper without elasticity for measuring PROPS, and not to use cotton thread or rubber bands.
2. When reading values, the line of sight should be parallel to the scale being read to avoid errors caused by different angles, preferably accurate to 0.1mm.
3. Due to the easy thermal expansion and contraction of finger blood vessels, there may be deviations in measurements at different temperatures and seasons. Measurements may be tighter in summer and looser in winter. It is recommended to take the average of multiple measurements at different times.
4. There are different versions of the ring size comparison table, such as international version, mainland version, Hong Kong version, etc. Different versions correspond to different ring sizes. When purchasing, it is important to be clear which version of the ring size chart the brand is using.